Clogged Waste Line

[Cindy Lawrence]

I have a 1986 Tolly 44 CPMY with a blockage in the sanitation line running from the aft head, through the engine room, up to the 40 gallon holding tank located under the V berth. The blockage occurs beyond the aft Y valve which diverts the waste for overboard disposal and is possibly in the ~10 foot black PVC pipe Tolly used for the long, straight run between the starboard engine and fuel tank. I am told that later 44's were modified to have a second holding tank in the aft of the boat for the aft head.
Two questions. Does anyone have any advice for unclogging the line? Right now we plan on disconnecting the flexible waste line from the PVC and try to run a snake into the run to locate and hopefully dislodge the blockage. The second question regards how the second holding tank was piped into the revised black water system on later 44's. Were there two Pumpout ports? Where was the tank located? Has anyone added a second holding tank and if so how was it plumbed?

[Steve Kraus]

some caution for this suggestion; My experiences are limited to 30' .

But, I would attempt to "TOWEL" seal an air compressor hose and apply some modulated air pressure originating at the head source. It will help to DISCONNECT  plumbing. as close to the  end run as possible or briefly overboard, instead of trying to pressure into the holding tank. 

Pressure buildup may be very slow but should purge in time.  Unintended consequences could be some back flow into the head. Potentially messy but that's what showers arevor. 

good luck. 

[David Seres]

I have a 1990 44 CPMY.  I have two black water tanks, one under the galley floor and another under the bed in the aft stateroom.  In my case, both heads are plumbed to the forward black water tank and the one under the bed is unused.  I have two pumpout ports, one for each tank.  The forward tank port is on the port side and the aft tank port is located in the well on the starboard side near the salon door.  As far as your blockage is concerned, you might try flushing down some Noflex digestor and letting it do its thing for a few days or longer to see if that might dissolve some of the blockage.  I put a teaspoon full of it in both heads every day and I have never had a problem with clogged lines. Good luck!  https://marinesan.com/noflex-digestor/